srs_fetcher.h

#ifndef SRS_FETCHER_H_INCLUDED
#define SRS_FETCHER_H_INCLUDED

/*
  Copyright (c) 2017, 2024, Oracle and/or its affiliates.

  This program is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License, version 2.0,
  as published by the Free Software Foundation.

  This program is designed to work with certain software (including
  but not limited to OpenSSL) that is licensed under separate terms,
  as designated in a particular file or component or in included license
  documentation.  The authors of MySQL hereby grant you an additional
  permission to link the program and your derivative works with the
  separately licensed software that they have either included with
  the program or referenced in the documentation.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License, version 2.0, for more details.

  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA
*/

#include "sql/gis/geometries.h"
#include "sql/gis/srid.h"
#include "sql/mdl.h"

namespace dd {
class Spatial_reference_system;
}

class Srs_fetcher {
 private:
  THD *m_thd;

  /**
    Take an MDL lock on an SRID.

    @param[in] srid Spatial reference system ID
    @param[in] lock_type Type of lock to take

    @retval false Success.
    @retval true Locking failed. An error has already been flagged.
  */
  bool lock(gis::srid_t srid, enum_mdl_type lock_type);

 public:
  Srs_fetcher(THD *thd) : m_thd(thd) {}

  /**
    Acquire an SRS from the data dictionary. Take a shared read lock on the
    SRID.

    @param[in] srid Spatial reference system ID
    @param[out] srs The spatial reference system

    @retval false Success.
    @retval true Locking failed. An error has already been flagged.
  */
  bool acquire(gis::srid_t srid, const dd::Spatial_reference_system **srs);

  /**
    Acquire an SRS from the data dictionary with the intent of modifying
    it. Take an exclusive lock on the SRID.

    @param[in] srid Spatial reference system ID
    @param[out] srs The spatial reference system

    @retval false Success.
    @retval true Locking failed. An error has already been flagged.
  */
  bool acquire_for_modification(gis::srid_t srid,
                                dd::Spatial_reference_system **srs);

  static bool srs_exists(THD *thd, gis::srid_t srid, bool *exists);
};

#endif  // SRS_FETCHER_H_INCLUDED